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Tungstophosphoric acid/zirconia composites prepared by the sol–gel method: An efficient and recyclable green catalyst for the one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes

Paper ID Volume ID Publish Year Pages File Format Full-Text
40689 45862 2012 7 PDF Available
Title
Tungstophosphoric acid/zirconia composites prepared by the sol–gel method: An efficient and recyclable green catalyst for the one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes
Abstract

Samples of zirconia modified with different contents of tungstophosphoric acid (TPA) were synthesized from zirconium propoxide via sol–gel reactions using polyethylene glycol as template and were characterized by different physicochemical techniques (BET, XRD, FT-IR, and 31P MAS-NMR). The SBET of the solids decreases and the microporosity increases with the increase of the TPA content. According to FT-IR and 31P MAS-NMR studies, the main species present in the samples is [PW12O40]3− anion, which was partially transformed into [P2W21O71]6− and [PW11O39]7− anions during the synthesis and drying steps. The XRD patterns of the modified samples exhibit neither the characteristic peaks of TPA nor those attributed to its decomposition products.Aryl-14H-dibenzo[a,j]xanthenes have been synthesized by a one-pot condensation of 2-naphthol and aryl aldehydes, catalyzed by tungstophosphoric acid/zirconia composites in a solvent-free medium using conventional heating. The present approach offers the advantages of clean reaction, simple methodology, short reaction time, and high yield. The reaction work-up is very simple and the catalyst can be easily separated from the reaction mixture and reused several times in subsequent reactions without appreciable loss of the catalytic activity.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (82 K)Download as PowerPoint slideHighlights► Zirconia modified with tungstophosphoric acid samples were synthesized. ► The SBET decreases and the microporosity increases with the increase of TPA content. ► The species present in the samples are [PW12O40]3−, [P2W21O71]6− and [PW11O39]7− anion. ► Aryl-14H-dibenzo[a,j]xanthenes have been synthesized by a one-pot condensation. ► Condensation of 2-naphthol and aryl aldehydes catalyzed by TPA/zirconia composites.

Keywords
Mesoporous zirconia; Heteropolyacids; 14-Aryl-14H-dibenzo[a,j]xanthenes; Heterogeneous catalysis; Solvent-free reaction
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Tungstophosphoric acid/zirconia composites prepared by the sol–gel method: An efficient and recyclable green catalyst for the one-pot synthesis of 14-aryl-14H-dibenzo[a,j]xanthenes
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Publisher
Database: Elsevier - ScienceDirect
Journal: Applied Catalysis A: General - Volumes 443–444, 7 November 2012, Pages 207–213
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Catalysis
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us